rs368373840

chr16-89531949-G-Achr16-89531949-G-C

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PM5

The NM_003119.4(SPG7):c.1033G>A(p.Ala345Thr) variant causes a missense change. The variant allele was found at a frequency of 0.0000192 in 1,614,102 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A345P) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: 𝑓 0.000039 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000017 (0 hom.)
• Consequence: SPG7 NM_003119.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 4.55

Genes affected

SPG7 (HGNC:11237): (SPG7 matrix AAA peptidase subunit, paraplegin) This gene encodes a mitochondrial metalloprotease protein that is a member of the AAA family. Members of this protein family share an ATPase domain and have roles in diverse cellular processes including membrane trafficking, intracellular motility, organelle biogenesis, protein folding, and proteolysis. Mutations in this gene cause autosomal recessive spastic paraplegia 7. Two transcript variants encoding distinct isoforms have been identified. [provided by RefSeq, Mar 2014]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 6 uncertain in NM_003119.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr16-89531949-G-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 436844.We mark this variant Likely_pathogenic, oryginal submissions are: {Pathogenic=1, Uncertain_significance=3, Likely_pathogenic=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SPG7	NM_003119.4	c.1033G>A	p.Ala345Thr	missense_variant	8/17	ENST00000645818.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SPG7	ENST00000645818.2	c.1033G>A	p.Ala345Thr	missense_variant	8/17		NM_003119.4	P2

Frequencies

GnomAD3 genomes AF: 0.0000394 AC: 6 AN: 152236 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000482

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000577

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000359 AC: 9 AN: 250854 Hom.: 0 AF XY: 0.0000368 AC XY: 5 AN XY: 135732

Gnomad AFR exome AF: 0.0000617

Gnomad AMR exome AF: 0.0000578

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000218

Gnomad SAS exome AF: 0.0000327

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000883

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000171 AC: 25 AN: 1461748 Hom.: 0 Cov.: 31 AF XY: 0.0000124 AC XY: 9 AN XY: 727202

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.0000447

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000756

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000135

Gnomad4 OTH exome AF: 0.0000497

GnomAD4 genome AF: 0.0000394 AC: 6 AN: 152354 Hom.: 0 Cov.: 32 AF XY: 0.0000403 AC XY: 3 AN XY: 74488

Gnomad4 AFR AF: 0.0000481

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.000578

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000575 Hom.: 0

Bravo AF: 0.0000680

TwinsUK AF: 0.00 AC: 0

ALSPAC AF: 0.000259 AC: 1

ESP6500AA AF: 0.000227 AC: 1

ESP6500EA AF: 0.00 AC: 0

ExAC AF: 0.0000330 AC: 4

Asia WGS AF: 0.000289 AC: 1 AN: 3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 05, 2023

The c.1033G>A (p.A345T) alteration is located in exon 8 (coding exon 8) of the SPG7 gene. This alteration results from a G to A substitution at nucleotide position 1033, causing the alanine (A) at amino acid position 345 to be replaced by a threonine (T). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Hereditary spastic paraplegia 7 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jul 08, 2023

This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 345 of the SPG7 protein (p.Ala345Thr). This variant is present in population databases (rs368373840, gnomAD 0.02%). This variant has not been reported in the literature in individuals affected with SPG7-related conditions. ClinVar contains an entry for this variant (Variation ID: 1407118). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt SPG7 protein function. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.26
BayesDel_addAF	Uncertain	0.060	T
BayesDel_noAF	Uncertain	0.11
Cadd	Uncertain	25
Dann	Uncertain	1.0
Eigen	Uncertain	0.61
Eigen_PC	Uncertain	0.53
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Pathogenic	0.98	D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.51	D
MetaRNN	Uncertain	0.71	D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.72	T
Polyphen		1.0, 1.0	.;.;D;.;.;.;.;.;D
Vest4		0.74
MVP		0.97
MPC		0.76
ClinPred		0.65	D
GERP RS		5.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.83
gMVP		0.75

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs368373840; hg19: chr16-89598357; COSMIC: COSV51947895; COSMIC: COSV51947895;